A coalition of seven consumer groups, representing 33 million Americans, denounced the Reagan administration's health, safety and regulatory policies yesterday, calling them a disaster for consumers.

"Consumers are worse off than they were a year ago when President Reagan took office," concluded the groups' 51-page report, "Warning: Reaganomics Is Harmful to Consumers."

Through budget cuts, the termination or relaxation of many pending regulations and a reduction in enforcement, the Reagan administration has undermined the government's consumer protection programs, many of them decades old, the coalition said.

"The damage done to consumer rights, services and protections by the Reagan administration's economic policies has been deep and far-reaching; furthermore, this trend is likely to continue and even accelerate in the coming year," the coalition said.

So concerned that further programs may be eliminated, the groups said the report was needed to alert Congress and the public about what they called Reagan's harmful policies. It was the first time consumer groups have worked together to evaluate an administration's activities.

To continue their efforts this year, the groups set up a 12-point consumer-action agenda to try, among other things, to preserve the role of the Federal Trade Commission in promoting competition and protecting consumers from unfair business practices, to prevent the deregulation of natural gas prices and to pre vent the federal preemption of state limits on interest rates.

The coalition included the Center for Science in the Public Interest, Community Nutrition Institute, Congress Watch, Consumer Federation of America, National Consumers League, and National Council of Senior Citizens.

Also participating was Consumers Union, whose Washington advocacy office had been scheduled to close down by the end of the month because of financial troubles at the parent organization, which publishes Consumer Reports. Last weekend, the board of directors agreed to keep the Washington office as well as its two other legal field offices open for at least another 18 months while the offices seek funds from other sources, including individuals and foundations.

Nonetheless, the offices will be operating at substantially reduced budgets. CU officials declined to say how sharply their budgets will be cut.

According to the coalition, the only good thing the Reagan administration has done for consumers is to bring down the rate of inflation. But the coalition added that Reagan does not deserve credit. It said that inflation is down because of his failure to keep unemployment down. Also contributing to the lower inflation rate is a glut in oil supplies that Reagan had little to do with.

The report charged:

Federal programs protecting the safety and quality of food supply have been a special target of the Reagan administration's efforts to reduce government. Also hit have been special assistance programs to make sure families obtain adequate nutrition.

Health, drug safety and information programs have been eliminated as a result of budget cuts and deregulation. At the same time, "The administration has made no attempts to contain health care costs, which are rising at 16 percent a year, far above the cost of living."

The administration has raised energy prices, while at the same time systematically beginning the dismantling of conservation programs and needed information programs to make consumers better buyers of high-energy-consuming appliances.